Loom operation indicator circuit

ABSTRACT

Determination of whether a textile machine, specifically a loom, is operating or not, is accomplished by the apparatus disclosed herein by means of sensing machine motion. A switch, either SPST, SPDT, or DPST, is mounted on the rocker shaft of the loom or other oscillating part of the loom essential to cloth production for oscillation therewith and is connected to remote RC circuitry which biases a transistor to an on state only while the switch is oscillating. A central computer senses the condition of the transistor for each of the looms so equipped in a mill, to produce information for management.

United States Patent Frederick A. Dunlap, III Clemson, S.C.

Apr. 26, 1968 Jan. 4, 1972 Greenwood Mllll Greenwood, S.C.

[ 72] Inventor [21 Appl. No. [22] Filed [45 Patented [73 Asaignee [54] LOOM OPERATION INDICATOR CIRCUIT 12 Claims, 8 Drawing Figs.

340/271, 139/336 [5 1] Int. Cl G08b 23/00 [50] Field of Search 340/267, 261, 279, 271; ZOO/61.48; 139/336, 341; 307/293,

2,280,114 4/194; Athy Primary Examiner-John W. Caldwell Assistant Examiner-Michael Slobasky Attorney-Cushman, Darby & Cushman ABSTRACT: Determination of whether a textile machine, specifically a loom, is operating or not, is accomplished by the apparatus disclosed herein by means of sensing machine motion. A switch, either SPST, SPDT, or DPST, is mounted on the rocker shaft of the loom or other oscillating part of the loom essential to cloth production for oscillation therewith and is connected to remote RC circuitry which biases a transistor to an on state only while the switch is oscillating. A central computer senses the condition of the transistor for each of the looms so equipped in a mill, to produce information for management.

PATENTED J N 4 72 SHEET 1 OF 2 INK E. ITUR PATENTED JAN 41972 SHEET 2 BF 2 in @l o 1 LOOM OPERATION INDICATOR cmcrmr DESCRIPTION OF THE PRIOR ART AND SUMMARY OF THE INVENTION This invention generally relates to data acquisition equipment and especially to apparatus for determining whether a textile machine is operating or not, and to the combination of suchappara'tus with a textile machine, such as a loom. In particular, the apparatusdetermines whether a textile machine part, which normally moves during operation is in motion, thereby determining whether the textile machine itself is operating.

Ina mill with a number of textile machines it is important to know which machines are in operation and which machines are not. These machines may be looms, spinning frames, knitting machines, or indeed any type of textile machine. This knowledge enables the mill management to make intelligent decisions relating to the material required for each machine and the type and quantity of finished products, such as cloth, which are being produced. In addition, since the pay of the workers operating these machines is often related to the time during whichthe machine is operating, this knowledge is important in determining payroll schedules and amounts.

Pick counters mounted on each machine have been used in the past to record the number of loom running cycles. However, such devices provide an output which must be periodically and manually read and which cannot be used to supply an immediate indication of the number of machinesoperating or a permanent record thereof.

Also, in the prior art, both optical and electrical means have been utilized in an attempt to determine when the machine is in operation. Most of the optical systems involve a beam of light which is interrupted only while the machine is operating, while the electrical systems have involved a switch such as a microswitch which remains closed during the whole operation of the machine and is open during nonoperating times, or vice versa, as in the Long et al. U.S. Pat. No. 3,340,537. However, both of these methods have been subject to failure in that they can be easily circumvented by shorting the switch contacts or blocking the optical beam with any solid object. This deception may be serious and prevalent if pay is dependent upon the operating time of the machine.

In contrast, in the embodiments of the present invention disclosed herein, such deception cannot be readily practiced because a continually changing or varying electrical signal is necessary to obtain an indicationof machine operation. For producing such' a signal switch means is mounted on a machine part which normally moves during machine opera tion. This produces a first signal which changes with time while the part is moving, and a second but steady signal, for example a zero signal, while the part is not moving.

These two signals may then be detected or changed in any suitable manner. In the embodiments disclosed herein, the signals are applied to an electrical circuit which produces a bilevel output signal having one level in response to the changing first signal indicating machine operation and a second level in response to the steady second signal indicating nonoperation.

The present invention is especially useful in the textile industry since it can be easily adapted to any textile machine which has a part that moves during operation. Since almost all textile machines have such a part, the invention can be used with a wide variety of textile machines. In the embodiments discussed below, only the switch means need to be mounted on the textile machine and the remainder of the circuitry can be located wherever convenient.

The remainder of the circuitry for a number of machines can then be grouped in a convenient location where the bilevel output voltages of each of the electrical circuits can be read. The circuits can be read sequentially, i.e. one at a time, and the information conveyed to a recorder, computer or othermechanismjn a sequential order form. This represents a considerable savings in equipment since only one detecting circuit per group is required and only one input line to the computer or other machinery per group. 7

In addition, the invention produces an electrical signal, and, in the embodiments discussed below, a bilevel signal, which is especially suitable for input into electronic digital processing equipment, so that a computer can determine at all times which machines are operating and act accordingly. The computer can provide quick replies to inquiries as well as to'control the machines and even route raw materials if desired.

Furthermore, in the embodiments discussed below, the moving part of the textile machine is not reqiiired'to move (oscillate, reciprocate, or rotate, for example) with any particular regularity or at a stable frequency. Detection over a range of speeds and considerable deviation from periodicity is possible. The invention can be operated with'virtually any textile machine at virtually any speed simply by changing the value of the circuit components. 7

Since only the switch itself is mounted on the textile machine, the system cannot be fooled by shorting the switch or cutting the wires; the part on whic'hthe switch'is mounted must actually move before operation is detected. 7

Other objects and advantages willbecome apparent from reading the detailed description of the invention set forth below in conjunction with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a loom in front elevation with a switch mounted upon its rocker shaft and leading to an electrical c'ircuit to indicate motion and hence operation of the textile machine in accordance with the present invention;

FIG. 2 shows a sectional view of FIG. 1 taken along'the lines 22 without background, illustrating one type of switch mounted upon the rocker shaft of the textile machine;

FIG. 3 schematically shows an electrical circuit in accordance with one embodiment of the invention;

FIG. 4 and 4a illustrate exemplary voltages across the capacitors shown in FIG. 3 plotted against time;

FIG. 5 schematically illustrates another embodiment of the invention; and

FIGS. 6 and 6a illustrate exemplary voltages across the capacitors in FIG. 5 plotted against time.

DETAILED DESCRIPTION OF THE DRAWINGS Reference is now made to FIG. 1 which'shows a typical'textile machine, for example a loom. Although the motion sensing device of this invention has been-especially designed for a loom, it can be used with and in combination withmany other types of textile machines such as knitting machines, spinning frames, or the like. The invention not only contemplates a separate motion sensing device perse which is useful with a textile machine, but also such a device incornbinatioh with a textile machine and in particular with a loom.

In the loom shown in FIG. 1 a shuttle 20 isdepicted moving between two shuttle boxes 22 and 24 carrying a pick 25 through the warp threads 26. The loomdepicted is not intended to be any particular type of loom but is merely intended to be representative of looms and textile machines in general. As is conventional, rocker shaft 30 oscillates back and forth about its axis thereby oscillating lay swords 32mm 34 which cause the reed 35 to pack the woven cloth after each trip by the shuttle 20 so that the cloth will be tightly woven. Hence, the rocker shaft 30 provides a convenient location for a mounting device 36 (see FIG. 2 also) which containsth'e switch 38 which is used in the FIGS. 3 and 5 circuits as described below to detect motion of the rocker shaft'30 and hence operation of the loom. It will of course be understood that any textile machine part that moves continually only while the machine is in operation can be easily usediristead 'of the rocker shaft, for example a part that oscillates or reciprocates (or even rotates if the switch has a slip ring output or the like) such as a'lay swo'rd 32 'or 34 'or'the'arinth'at drives the take up reel (not shown).

Switch 38 may be a two terminal (SPST) switch or a three terminal (DPST or SPDT) switch of the mercury type as shown in the embodiments in FIGS. 3 and 5 or indeed any type of appropriate switch including a reed or disturb switch. This switch 38 is mounted on the rocker shaft so that the oscillating motion of the rocker shaft 30 causes the switch to oscillate between first and second electrical states to have a first condition when the shaft 30 is moving and a second condition when it is not, as described in detail below so that motion or lack of motion of the rocker shaft 30 and hence the state of operation or nonoperation of the machine is sensed.

The switch 38 is electrically connected by a cable 40 to the electrical circuitry in block 42 which is preferably located at a remote distance in a locked cabinet in another room. The electrical circuitry in block 42 may be the type illustrated in FIG. 3 or 5. Cable 40, which may be secured by straps 44 to rocker shaft 30 and then pass under the floor to the remote location of circuitry 42, is a two or three wire cable according to whether the FIGS. 3 or 5 circuitry is employed. From electrical circuitry 42 a signal may be obtained by computer 46, indicating whether rocker shaft 30 is oscillating and hence whether the loom is operating.

Computer 46 also receives signals from all other looms in the mill similarly equipped and correlates these signals to provide whatever information is desired. It may be convenient to group some of the electrical circuits 42 together. The mill would then be divided into a number of such groups. In each group each circuit 42 can then be sensed sequentially and the information passed on to the computer 46. Each circuit 42 can then be checked every minute or at whatever interval desired to determine whether the machine associated with it is operatmg.

Other systems have utilized graphical and other recorders to provide a permanent and accurate record of machine operation. For example in the patent to Long et al., U.S. Pat. No. 3,340,537 counters and recorders, including a drum recorder, are used to record operating and nonoperating times of a textile machine. This invention also can be used with recorders, counters or other equipment and is not limited to use with computers.

A digital computer, however, can act upon the information received as well as record it. The. computer can respond quickly to inquiries about any given machine, and provide all necessary data nearly instantaneously. In addition, all data on all machines can be produced regularly in convenient printed form. The computer can further provide punched cards for payroll schedules or simply prepare the payroll on the basis of its own information. The computer can in addition control the output of each of the different produces being made properly route raw materials.

Switch 38 may be mounted on the rocker shaft 30 by any means which keeps the switch firmly in place while the rocker shaft 30 oscillates. FIG. 2 shows one way by which the switch 38 may be secured to the rocker shaft 30. An inverted U- shaped bolt 48 fits around the rocker shaft 30 and a block 50 is secured below the rocker shaft 30 by passing the bolts 48 through two holes in the block 50 and applying nuts 52 and 54 to the threaded ends of the bolt 48. The switch 38 may be attached to the block 50 or sealingly fastened within it as shown. Fastening the switch 38 inside the block 50 provides an additional measure of safety against tampering. As conventional for mercury switches, it includes a housing containing a mercury ball 56. In addition it contains a pair of contacts or terminals at both ends for a FIG. 3 embodiment or at one end only for a FIG. 5 embodiment. When rocker shaft 30 is oscillating, the ball of mercury 56 moves from one end of the switch 38 to the other so that the contacts therein are alternately electrically connected and disconnected.

Reference is now made to FIG. 3 which discloses a circuit capable of detecting motion of a moving part in a textile machine such as a loom. Switch 38 in this embodiment is a three terminal switch 60 which may be of the single pole double throw type (SPDT) or the double pole single throw type (DPST) illustrating as including ganged switches 62 and 64.

With either type, the switch is in a first state when one set of contacts is closed (switch 62 for example) and the other contact (switch 64) is open, and in a second state when the reverse arrangement exists. One or the other of switches 62 and 64 will always be open and the other closed. The switch 60 then has a first condition when the switches 62 and 64 are opening and closing and a second condition when they are not. When switch 64 is closed and switch 62 is open, capacitor 66 is charged from a DC source 68 through resistor 70, while capacitor 72 discharges somewhat via resistor 74. When switch 60 reverses to its other state to open switch 64 and close switch 62, the charge on capacitor 66 charges capacitor 72 transiently via charging resistor 76, resulting in voltage being applied to limiting resistor 78 and across base 80 and emitter 82 of an NPN switching transistor 84 to drive it into conduction. Computer 46 of FIG. 1 connects to the transistor collector 86 to sense conduction and nonconduction thereof. Since the two capacitors 66 and 72 are effectively isolated from the source 68 during discharge, source 68, which may be rectified AC, does not have to be particularly well regulated or filtered.

In the graphs of FIG. 4, the voltage V represents the voltage across capacitor 66 and the voltage V represents the voltage across capacitor 72. If the source 68, which may be at a potential of about 20 volts, is applied or activated while the switch 64 is open, no current flows through resistor 70 and the circuit components are not effected. As discussed below in connection with the circuit of FIG. 5, the source 68 may also supply the power requirements of a number of motion detection systems associated with a number of different machines. It may be desirable to mount switch 38 in either embodiment so that when the machine is not operating, the switch opens the path from the direct current source 68 and no power is consumed. This results in a saving in energy losses and may increase the lifetime of the resistor 70 and capacitor 66.

When switch 64 closes, for example at a time represented as t on the graph in FIG. 4, and switch 62 thereby opens, capacitor 66 is charged through resistor 70 toward the voltage of the source 68. Should switch 64 remain closed, capacitor 66 will continue to charge exponentially as shown by line 88.

When switch 64 opens at time t and switch 62 closes, capacitor 66 begins to discharge through resistor 76 and then through capacitor 72 and resistor 74, with a time constant which is a function of the values of resistors 74 and 76 and capacitor 72. The voltage built upon capacitor 72 is shown in FIG. 4a between times t, and t Some discharge also occurs through resistor 78 after the voltage V across capacitor 72 is sufficient to drive transistor 84 into conduction. The capacitor 72 at the same time begins to exhibit a net and transient increase in charge which is the mathematical sum of two exponential functions with different time constants. Should switch 62 remain closed the voltage V across capacitor 72 will peak and then decay toward zero, as shown by dash line 90 in FIG. 4a, as the two exponential functions decay toward zero. Similarly, the voltage across capacitor 66, will also decay toward zero as shown by dash line 92 in FIG. 4.

If, however, the switch 62 opens, for example at time 1,, capacitor 66 will be recharged at the same rate that it was initially charged and voltage V will begin to exponentially decay through resistor 74 and resistor 78. Should the switch 64 remain closed voltage V, will continue to decay along the dashed line 94 until it reaches a steady state value of essentially zero volts.

However, if switch 64 opens and switch 62 closes at a time such as t the voltage across capacitor 72 again rises transiently and the voltage across capacitor 66 decay. The alternate opening and closing of switches 62 and 64, which make up three terminal switch 60, will then ensure that capacitor 72 will remain at a changing but positive voltage which is sufficient to maintain the NPN-transistor 84 in a state of conduction. A PNP-transistor can of course be substituted merely by reversing the polarity of the DC source 68. Should the switches 64 and 62 stop in either state due to the cessation of oscillation of rocker shaft 30 then the voltage across capacitor 72 will decay to zero in either case and transistor 84 will then go into a detectable state of nonconduction. The rocker shaft 30, or whateverpart of the switch is mounted on, must actually be in continual motion for the transistor 84 to remain conductive.

In FIG. 5, another circuit is shown which is capable of sensing the motion of a moving part in a typical textile machine, for example, the oscillating motion of the rocker shaft 30 of the textile machine shown in FIG. 1. This circuit is further described and specifically claimed in application Ser. No. 724,389, filed concurrently herewith, the disclosure of which is incorporated hereinto by reference. Switch 38, which in this particular circuit is a two terminal switch having a first electrical state when its switch arm'98 is open an a second state when that arm is closed, is mounted in the same way as described in connection with FIG. 2, and automatically and alternately opens and closes if the rocker shaft 30 is oscillating and hence the loom is operating. The capacitors 100 and 102 then are alternately charged and discharged provided that the switch is opening and closing. The presence of voltage across the capacitor 102, which, as explained below, occurs only when the switch arm 98 is alternately opening and closing, maintains a positive potential between the base and an emitter of the NPN transistor 104, thereby keeping transistor 104 in a state of conduction which can be sensed and which thereby indicates the motion of the rocker shaft 30 and hence operating of the loom.

The operation of the circuit of FIG. 5 is now discussed in detail. If the direct circuit source 106 is applied or activated when the switch 38 is in a closed position, current will simply flow through the resistor 108 and the switch 38 without disturbing any of the other components of the circuit. A direct current voltage of about volts has been satisfactory for source 106. The source 106 may also supply the power requirements of a number of systems similar to the system described herein associated with a number of different machines. It may be desirable to mount the switch 38 so that, when the machine is not operating, the switch is open and current will not flow in the steady state condition through resistor 108. However, if switch 38 is in or moves to an open position after the source 106 is activated, current flows through resistor 108, capacitor 100, diode 112 and the parallel combination of capacitor 102 and resistor 114. Since the NPN- transistor 104 will be in a state of nonconduction, no current can immediately flow through the resistor 116. A PNP- transistor can be substituted for transistor 104 merely by reversing the polarity of the source 106 and the direction of the diodes 112 and 126.

In the graph of FIG. 6, when switch 38 opens as at time t the voltage across capacitor 100, which is labeled V begins to rise exponentially and so does the voltage V across capacitor 102 as shown in FIG. 6a. After the voltage between the base and emitter of transistor '1 14 is great enough to drive the transistor into conduction, the rate of charging will decrease since the resistor 116 is effectively connected in parallel with resistor 114. The resistor 116 also limits the flow of current through transistor 104 to a value below that which might damage the transistor 104. If switch 38 remains open, the capacitor 100 will continue to charge as shown by dash line 120 until the voltage V is essentially equal to the voltage across the direct current source 106.

As above indicated, the same time that capacitor 100 is charging between times t and t,, capacitor 102 is also exhibiting a net and transient increase in charge as shown in FIG. 6a. This is mathematically the sum of a positive function having an exponential decay and a negative function having an exponential decay, each of which has the same initial value but a different time constant. If the switch 38 remains in an open position as it would if the loom were not operating then, the voltage V wilfpeak and then decay along dash line 123 toward a steady state value of zero volts as the two exponential functions, the sum of which makes up V each decay toward a steady state value of zero volts.

However, if the rocker shaft or other moving part is oscillating, switch 38 will close before the voltage across capacitor charges to the voltage of the source 106 or the voltage across capacitor 102 decaysto zero. It may be desirable to choose the capacitor and resistor values so that switchingwill occur approximately at a time when voltage V is maximum.

For the purpose of discussion, it is assumed that switch-.38 closes at a time which is noted by t, in the graphs of FIG. 6, and which is near the maximum voltage which can appear across capacitor 102. It will, of course, be understoodthat-the component values of the resistors 108, 114 and 116 and the capacitors 100 and 102 can be chosen so that the times at which opening or closing occurs will be at another location during the charging or discharging of the capacitors 100 and 102 and that switching may occur at times other than l, t t etc. Furthermore, time intervals between t and t, and 1 etc. need not be uniform or even approximately the same.

The closing of switch 38 connects capacitor 100 across the series combination of resistor 124 and diode 126'. When switch 38 is open, the diode 126 prevents the passage of current through itself and hence through resistor 124, since point 128 is at a higher potential than point 130. However, the closing of switch 38 connects point 132, which is at a higher potential than point 128, to point 130 so that-current flows through resistor 124 and diode 126, and capacitor 100 discharges through resistor 124. This discharge of capacitor 100 is shown in FIG. 6 by the exponential voltage V decay between the time t, when switch 38 closes and time 1 when it reopens. If switch 38 remains closed V100 Will decay toward zero along the dash line 134. It will, of course, be understood that the rate of discharge of capacitor 100 can be easily controlled by changing the value of resistor 124 and hence the rate of discharge. It may be desirable to discharge the capacitor 100 quickly as shown in FIG. 6 andhence a value of resistor 124 would be chosen which would be appropriate to accomplish this.

The closing of switch 38 also isolates capacitor 102 from capacitor 100 since diode 112 now prevents the passage of current between points 128 and 136 so that capacitor 102 also discharges exponentially, as shown in FIG. 6a between times t, and t This discharge is primarily through resistor 114 although some current may flow through resistor 116 and transistor 104 until transistor 104 becomes nonconductive. If the loom stops operating while switch 38 remains closed, the voltage across capacitor 102, decays to zero as shown along the dashed line 138 in FIG. 6a, with the result that the base emitter voltage of transistor 104 is reduced below the value necessary to maintain the transistor 104 in a state of conduction.

If, however, switch 38 reopens at a time t the voltage across capacitor 102 will again build up in the same manner as when switch 38 was initially opened. Similarly, voltage across capacitor 100 will rise exponentially in the same manner as when switch 38 was initially opened. The time constant however will be slightly decreased since the resistor 116 is effectively in parallel with the resistor 114 because the transistor 104 is in conductive state. This process of alternate charging and discharging will be repeated as long as switch 38 is periodically opening and closing, so that the detectable state of conduction or nonconduction of transistor 104 will indicate motion or lack of motion of rocker shaft 30, and hence operation or lack of operation of the loom. It will be appreciated that the motion of the rocker shaft 30, or other moving part upon which the switch 38 is mounted, need not be precisely periodic nor operated at the same frequency at all times.

The circuit discussed in FIG. 5 is capable of indicating motion even if the frequency of the rocker shaft should gary or be slightly aperiodic. Looms, which are but one type of textile machine with which the present invention may be used or combined, often operate a a frequency of about I 76 cycles per minute but can vary from below 80 cycles per minute to above 360 cycles per minute. The circuit is then capable of detecting motion should motion vary from that expected and the value of the circuit components can be easily changed to accommodate any machine which has moving parts operating at nearly any speed.

A simple type of circuit for sensing the conduction or nonconduction of transistor 104 as shown in FIG. includes a switch 140 which connects a source of direct current 142 and a resistor 144 between the collector and emitter of transistor 104. When switch 140 is closed the current through or voltage across resistor 144 may be sensed to determine whether transistor 104 is in a conductive or a nonconductive state. The computer 46 of FIG. 1 may operate similarly as to the electrical circuitry for each loom. For example, it may be convenient to locate the electrical circuitry for a group of looms together and utilize one sensing circuit to sense each of the electrical circuits from each of the looms sequentially. Each of the groups of electrical circuitry would then be linked to the computer 46 by one line which carries the signal representing each of the machines, sequentially. This arrangement results in a considerable savings in wiring and electrical components. The checking of the operation of the machine could take place at intervals of one minute or any other convenient interval.

Summarizing, the circuit of FIG. 3 operates by alternately charging a first capacitor 66 from a direct current source 68 and then discharging that capacitor 66 through a parallel combination of another capacitor 72 and a resistor 74 so that the charge on the second capacitor 72 rises transiently. While the first capacitor 66 is again charging, the second capacitor 72 is discharging primarily through resistor 74 so that the alternate charging and discharging of the second capacitor 72 results in a net charging, but positive, voltage between the base and emitter of a transistor 84, thereby maintaining the transistor in a detectable, conductive state whenever the machine is operating. The alternate charging and discharging is caused by movement of a three terminal switch 60.

Should the three terminal switch 60 shown in FIG. 3 stop in a position so that the first capacitor is charging, the second capacitor 72 will simply discharge completely to its steady state value of zero volts through its parallel resistor 74 until the transistor 84 becomes nonconductive. If the switch 60 stops when the first capacitor 66 is discharging transiently through the parallel connected second capacitor 72 and resistor 74, the voltage across both capacitors will eventually decay to a steady state value of zero volts, driving the transistor 84 into nonconduction. The periodic charging and discharging which occurs when the machine is operating prevents the second capacitor 72 from reaching its steady state value of zero volts. The result is that the transistor 84 is in a state of conduction only when the switch 60 is actually switching between first and second electrical states so that the second capacitor cannot arrive at its steady state value.

Both of the capacitors in FIG. 5 on the other hand are charged when the switch 38 is open and both discharge when it is closed, each through its own resistor which is isolated from the other capacitor. As in the circuit shown in FIG. 3, the second capacitor recharges only transiently and will decay to a potential of zero volts in steady state. However, the constant opening and closing of switch 38 prevents the second capacitor 102 from reaching steady state, and keeps it charged. A transistor 104 is connected across the second capacitor so tat when that capacitor is charged the voltage between the base and emitter is sufficient to keep the transistor 104 in a detectable state of conduction.

Many changes and modifications of the above structure and circuitry is possible without departing from the spirit of the invention. Although mercury tilt switches have been discussed particularly, many other switches such as reed or disturb switches may also be used. In addition the output transistor may be either a NPN- or PNP-type depending in the polarity of the direct current source and, in the circuit of FIG. 5, the direction of the diodes. The transistor merely operates as an on-off bilevel output device and can be easily replaced with any other type of appropriate solid state device or other switch device, such as a relay. The switch can also be located on any appropriate moving part of the textile machine and is not intended to be limited to the rocker shaft. Further, the invention contemplates a motion detection system to be used with a textile machine as well as in combination with a textile machine.

Accordingly, the scope of the invention is intended to be 5 limited only by the scope of the appended claims.

What is claimed is:

1. Apparatus for use with a textile machine of the type which has a part that moves in a given manner only during operation of said machine, comprising:

switch means having first and second electrical states and adapted to oscillate between said first and second states only while said part moves in said given manner, thereby sensing operation of said machine,

electric circuit means connected to said switch means for exhibiting a first only when said switch means is oscillating between said states as aforesaid to indicate operation of said machine and for exhibiting a second output signal during the absence of oscillation of said switch means, regardless of its electrical state then, to indicate nonoperation of said machine comprising RC means including connected first and second RC circuits the first of which includes a first capacitor connected to said switch means for alternate charge and discharge, respectively, during said first and second electrical states and the second of which is connected to said switching device input and wherein said electric circuit means includes a DC source connected to said first RC circuit by said switch means for causing the said alternate charge and discharge of said first capacitor to develop in said second RC circuit a charge sufficient to maintain said switching device in an on condition only during oscillation of said switching means, and

a bilevel switching device having off and on conditions for producing said first and second output signals and having an input connected to said RC means for operation of said switching device in one of said conditions only while said switch means is oscillating as aforesaid and in the other of said conditions while said switch means does not oscillate.

2. Apparatus as in claim 1 wherein said switch means includes a three terminal switch.

3. Apparatus as in claim 1 wherein said switch means is a mercury switch having a housing containing electrical contacts in at least one of the opposite ends of the housing and a ball of mercury which moves during a part of each oscillation to one of said ends to connect the contacts there and establish said first state and moves during another part of each oscillation to the other end of said housing to establish said second state.

4. A textile machine in combination with the apparatus of claim 1 and comprising a loom having as said moving part a rocker shaft on which said switch means is mounted for oscillation as aforesaid.

5. Apparatus for use with a textile machine of the type which has a part that moves in a given manner only during operation of said machine, comprising:

switch means having first and second electrical states and adapted to oscillate between said first and second states only while said part moves in said given manner, thereby sensing operation of said machine, and,

electric circuit means connected to said switch means for exhibiting a first output signal only when said switch means is oscillating between said states as aforesaid to indicate operation of said machine and for exhibiting a second output signal during the absence of oscillation of said switch means, regardless of its electrical state then, to indicate nonoperation of said machine, including a first capacitor and a first resistor connected in parallel, said capacitor having a charge only when said switch is oscillating between said first and second electrical states.

6. A system as in claim 5 wherein said circuit means includes a transistor and wherein said first capacitor is con- 75 nected between the base and emitter of said transistor.

7. A system as in claim 6 wherein said switch means includes three contacts and is in said first state when a first contact connects a second contact and is in said second state when said first contact connects a third contact.

8. A system as in claim 7 wherein said circuit means includes a second capacitor connected between said emitter of said transistor and said first contact, and a source of direct current, so that said source is connected across said second capacitor when said switch connects said first contact and said second contact, and said second capacitor is connected across said first capacitor when said switch connects said first contact and said third contact.

9. Apparatus for indicating motion in a textile machine of the type which has a part that moves only during operation of said machine, comprising:

a source of direct current voltage,

a first capacitor,

a second capacitor and a resistor connected in parallel, and

switch means adapted to be mounted on said machine part so as to cause said first capacitor to be alternately charged by said source and discharged through said second capacitor and said resistor when said part is moving, so that said second capacitor remains charged only as long as said part is moving.

10. A system as in claim 9 including a transistor having a base and emitter between which said second capacitor is connected for providing an output indicating whether said part is moving.

11. Apparatus for indicating motion in a textile machine of the type which has a part that moves only during operation of said machine, comprising:

switch means having a plurality of contacts and adapted to be mounted on said machine part to alternately connect a first contact of said plurality of contacts to one and then another of two other contacts of said plurality of contacts,

a first resistor,

a source of direct current electrical potential having one polarity linked to said one of two other contacts via said first resistor a first capacitor connected between said first contact and the other polarity of said source,

a second resistor connected at one end to said another contact,

a second capacitor connected between the end of said second resistor opposite said one end and said other polarity of said source so that when said switch is alternately connecting said contacts said second capacitor retains a charge,

a third resistor connected in parallel with said second capacitor,

a fourth resistor having one end connected to said end opposite said one end of said second resistor, and

a transistor having its base connected to the end opposite said one end of said fourth resistor and its emitter to said other polarity of said source, so that said transistor is conductive when said second capacitor has at least a given charge.

12. A textile machine in combination with said apparatus of claim 11 and comprising a loom having as said moving part a rocker shaft on which said switch means is mounted go oscillate therewith and effect said alternate connections. 

1. Apparatus for use with a textile machine of the type which Has a part that moves in a given manner only during operation of said machine, comprising: switch means having first and second electrical states and adapted to oscillate between said first and second states only while said part moves in said given manner, thereby sensing operation of said machine, electric circuit means connected to said switch means for exhibiting a first only when said switch means is oscillating between said states as aforesaid to indicate operation of said machine and for exhibiting a second output signal during the absence of oscillation of said switch means, regardless of its electrical state then, to indicate nonoperation of said machine comprising RC means including connected first and second RC circuits the first of which includes a first capacitor connected to said switch means for alternate charge and discharge, respectively, during said first and second electrical states and the second of which is connected to said switching device input and wherein said electric circuit means includes a DC source connected to said first RC circuit by said switch means for causing the said alternate charge and discharge of said first capacitor to develop in said second RC circuit a charge sufficient to maintain said switching device in an on condition only during oscillation of said switching means, and a bilevel switching device having off and on conditions for producing said first and second output signals and having an input connected to said RC means for operation of said switching device in one of said conditions only while said switch means is oscillating as aforesaid and in the other of said conditions while said switch means does not oscillate.
 2. Apparatus as in claim 1 wherein said switch means includes a three terminal switch.
 3. Apparatus as in claim 1 wherein said switch means is a mercury switch having a housing containing electrical contacts in at least one of the opposite ends of the housing and a ball of mercury which moves during a part of each oscillation to one of said ends to connect the contacts there and establish said first state and moves during another part of each oscillation to the other end of said housing to establish said second state.
 4. A textile machine in combination with the apparatus of claim 1 and comprising a loom having as said moving part a rocker shaft on which said switch means is mounted for oscillation as aforesaid.
 5. Apparatus for use with a textile machine of the type which has a part that moves in a given manner only during operation of said machine, comprising: switch means having first and second electrical states and adapted to oscillate between said first and second states only while said part moves in said given manner, thereby sensing operation of said machine, and, electric circuit means connected to said switch means for exhibiting a first output signal only when said switch means is oscillating between said states as aforesaid to indicate operation of said machine and for exhibiting a second output signal during the absence of oscillation of said switch means, regardless of its electrical state then, to indicate nonoperation of said machine, including a first capacitor and a first resistor connected in parallel, said capacitor having a charge only when said switch is oscillating between said first and second electrical states.
 6. A system as in claim 5 wherein said circuit means includes a transistor and wherein said first capacitor is connected between the base and emitter of said transistor.
 7. A system as in claim 6 wherein said switch means includes three contacts and is in said first state when a first contact connects a second contact and is in said second state when said first contact connects a third contact.
 8. A system as in claim 7 wherein said circuit means includes a second capacitor connected between said emitter of said transistor and said first contact, and a source of direct current, so that said source is connected across sAid second capacitor when said switch connects said first contact and said second contact, and said second capacitor is connected across said first capacitor when said switch connects said first contact and said third contact.
 9. Apparatus for indicating motion in a textile machine of the type which has a part that moves only during operation of said machine, comprising: a source of direct current voltage, a first capacitor, a second capacitor and a resistor connected in parallel, and switch means adapted to be mounted on said machine part so as to cause said first capacitor to be alternately charged by said source and discharged through said second capacitor and said resistor when said part is moving, so that said second capacitor remains charged only as long as said part is moving.
 10. A system as in claim 9 including a transistor having a base and emitter between which said second capacitor is connected for providing an output indicating whether said part is moving.
 11. Apparatus for indicating motion in a textile machine of the type which has a part that moves only during operation of said machine, comprising: switch means having a plurality of contacts and adapted to be mounted on said machine part to alternately connect a first contact of said plurality of contacts to one and then another of two other contacts of said plurality of contacts, a first resistor, a source of direct current electrical potential having one polarity linked to said one of two other contacts via said first resistor a first capacitor connected between said first contact and the other polarity of said source, a second resistor connected at one end to said another contact, a second capacitor connected between the end of said second resistor opposite said one end and said other polarity of said source so that when said switch is alternately connecting said contacts said second capacitor retains a charge, a third resistor connected in parallel with said second capacitor, a fourth resistor having one end connected to said end opposite said one end of said second resistor, and a transistor having its base connected to the end opposite said one end of said fourth resistor and its emitter to said other polarity of said source, so that said transistor is conductive when said second capacitor has at least a given charge.
 12. A textile machine in combination with said apparatus of claim 11 and comprising a loom having as said moving part a rocker shaft on which said switch means is mounted to oscillate therewith and effect said alternate connections. 